相关论文: A Comprehensive Study of Broad Absorption Line Qua…

We present a sample of 68 low-z MgII low-ionization broad absorption-line (loBAL) quasars. The sample is uniformly selected from the SDSS5 according to the following criteria: (1) 0.4<z<0.8, (2) median S/N>7, and (3) MgII absorption-line…

We report the discovery of unusual broad absorption lines (BALs) in the bright quasar SDSS J075133.35+134548.3 at z~1, and present a detailed study of BAL and emission lines using the archived and newly obtained optical and NIR…

We report the discovery of Balmer broad absorption lines (BALs) in the quasar LBQS 1206+1052 and present a detailed analysis of the peculiar absorption line spectrum. Besides Mg II $\lambda \lambda 2796, 2803$ doublet, BALs are also…

We report the discovery of the first HeI*\lambda 10830 broad absorption line quasar FBQS J1151+3822. Using new infrared and optical spectra, as well as the SDSS spectrum, we extracted the apparent optical depth profiles as a function of…

I report the discovery of blueshifted broad absorption line (BAL) troughs in at least six transitions of the Balmer series of hydrogen (Hbeta to H9) and in CaII, MgII and excited FeII in the quasar SDSS J125942.80+121312.6. This is only the…

We present 13 Broad Absorption Line (BAL) quasars, including 12 new objects, which were identified in the Sloan Digital Sky Survey (SDSS) and matched within 2'' to sources in the FIRST radio survey catalog. The surface density of this…

The Sloan Digital Sky Survey has confirmed the existence of populations of broad absorption line (BAL) quasars with various unusual properties. We present and discuss twenty-three such objects and consider the implications of their wide…

We present a detailed study of the optical and NIR emission and absorption line spectrum of the quasar SDSS J163345.22+512748.4. We discovered on the newly acquired NIR spectrum a highly meta-stable neutral helium broad absorption line…

We study the X-ray and optical properties of 16 Broad Absorption Line (BAL) quasars detected in about 3 degree square region common to the wide synoptic (W-1) component of the Canada-France-HawaiiTelescope Legacy Survey (CFHTLS) and the XMM…

Quasar accretion-disk outflows might play an important role in galaxy evolution, but they are notoriously difficult to study due to line saturation and blending problems in the Ly-alpha forest. We circumvent these problems by constructing…

SDSS J083942.11+380526.3 ($z=2.315$) is a FeLoBAL quasar that exhibits visible Balmer absorption lines (H$\alpha$), implying a significant $n=2$ population. The quasar also shows an array of absorption lines, including \oi, \niii, \feii,…

The Sloan Digital Sky Survey has discovered a population of broad absorption line quasars with various extreme properties. Many show absorption from metastable states of FeII with varying excitations; several objects are almost completely…

We have discovered two low-ionization broad absorption line quasars in programs to obtain optical spectra for radio-selected quasar candidates from the VLA FIRST Survey (Becker, White, & Helfand 1995). Both belong to the extremely rare…

Broad absorption line (BAL) quasars are characterized by gas clouds that absorb flux at the wavelength of common quasar spectral features, although blueshifted by velocities that can exceed 0.1c. BAL features are interesting as signatures…

We study high-resolution spectra of the `overlapping-trough' low-ionization broad absorption line (LoBAL) quasar SDSS J030000.56+004828.0. The CaII, MgII and MgI column densities in this object are the largest reported to date for any BAL…

We present new spectropolarimetric observations of 8 radio-loud broad absorption line (BAL) quasars, and combine these new data with our previous spectropolarimetric atlases (of both radio-loud and radio-quiet objects) in order to…

Broad absorption lines (BALs) found in a significant fraction of quasar spectra identify high-velocity outflows that might be present in all quasars and could be a major factor in feedback to galaxy evolution. Understanding the nature of…

Broad absorption line quasars (BALQs) present a large diversity in their broad absorption line (BAL) profiles. To investigate what physical parameters underlie this diversity, we construct a sample of BALQs which covers lambda_rest ~…

We present absorption variability results for 134 bona fide \mgii\ broad absorption line (BAL) quasars at 0.46~$\lesssim z \lesssim$~2.3 covering days to $\sim$ 10 yr in the rest frame. We use multiple-epoch spectra from the Sloan Digital…

We report spectropolarimetry of 30 radio-selected broad absorption line (BAL) quasars with the Keck Observatory, 25 from the sample of Becker et al. (2000). Both high and low-ionization BAL quasars are represented, with redshifts ranging…